Overview
ISO 11512:1995 - "Machinery for forestry - Tracked special machines - Performance criteria for brake systems" specifies uniform test methods and performance criteria for the service, secondary and parking brake systems of self‑propelled tracked forestry machines with a maximum design speed of 20 km/h. The standard defines what to measure, how to set up tests and the minimum brake performance needed to assess safety and functionality of braking on low‑speed tracked forestry equipment.
Key topics and requirements
- Scope and definitions: Applies to self‑propelled tracked special forestry machines (≤20 km/h). Defines brake system types (service, secondary, parking), common components, machine mass (m) and slope capability (α).
- Required systems: Every machine must have a service, a secondary and a parking brake. Brake disconnects that allow disabling are prohibited except for specific relocation or cold‑start provisions.
- Control forces: Maximum test control forces are specified (e.g., finger grasp 20 N; hand grasp up to 400 N; fore‑aft/sidearm 300 N; foot treadle 350 N; foot pedal 600 N) to ensure operator accessibility and ergonomics.
- Test methods:
- Towing test for service and secondary brakes: towing or driving with transmission neutral at 10–40% of maximum level speed (ISO 6014 referenced) and measuring brake retarding force and control forces.
- Static pull (parking brake) test: machine held stationary while a towing force is applied to verify holding capability.
- Test course requirements: relatively flat, smooth surface (≤1% grade in travel direction; ≤3% transverse) with adequate traction.
- Performance criteria: Brake retarding force expressed relative to machine mass and slope capability:
- Service brake: 9.8·m·sin(α) N
- Secondary brake: 4.9·m·sin(α) N (at least one track)
- Parking brake: 9.8·m·sin(α) N (static holding/pull)
(where m = machine mass, α = slope capability)
- Reliability and common components: Failure of any single common component must not reduce stopping effectiveness below the secondary brake performance.
- Instrumentation and accuracy: Measurements must meet specified accuracy classes to ensure repeatable test results.
Applications and who uses it
- Manufacturers of tracked forestry machines (design validation, type approval)
- Test laboratories and certification bodies conducting brake performance testing
- Safety and compliance engineers drafting operator manuals and maintenance procedures
- Fleet owners and procurement specialists verifying braking capability for safe operation on slopes and during towing
- Regulators referencing harmonized brake test protocols for field inspections
Related standards
- ISO 6014 - determination of ground speed (used for test speeds)
- ISO 6814 - machinery for forestry vocabulary (definitions)
Keywords: ISO 11512:1995, forestry machinery, tracked special machines, brake systems, brake performance, towing test, parking brake, service brake, secondary brake, brake retarding force.
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